linux/fs/sysv/namei.c
<<
>>
Prefs
   1/*
   2 *  linux/fs/sysv/namei.c
   3 *
   4 *  minix/namei.c
   5 *  Copyright (C) 1991, 1992  Linus Torvalds
   6 *
   7 *  coh/namei.c
   8 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
   9 *
  10 *  sysv/namei.c
  11 *  Copyright (C) 1993  Bruno Haible
  12 *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
  13 */
  14
  15#include <linux/pagemap.h>
  16#include "sysv.h"
  17
  18static int add_nondir(struct dentry *dentry, struct inode *inode)
  19{
  20        int err = sysv_add_link(dentry, inode);
  21        if (!err) {
  22                d_instantiate(dentry, inode);
  23                return 0;
  24        }
  25        inode_dec_link_count(inode);
  26        iput(inode);
  27        return err;
  28}
  29
  30static int sysv_hash(const struct dentry *dentry, struct qstr *qstr)
  31{
  32        /* Truncate the name in place, avoids having to define a compare
  33           function. */
  34        if (qstr->len > SYSV_NAMELEN) {
  35                qstr->len = SYSV_NAMELEN;
  36                qstr->hash = full_name_hash(qstr->name, qstr->len);
  37        }
  38        return 0;
  39}
  40
  41const struct dentry_operations sysv_dentry_operations = {
  42        .d_hash         = sysv_hash,
  43};
  44
  45static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
  46{
  47        struct inode * inode = NULL;
  48        ino_t ino;
  49
  50        if (dentry->d_name.len > SYSV_NAMELEN)
  51                return ERR_PTR(-ENAMETOOLONG);
  52        ino = sysv_inode_by_name(dentry);
  53
  54        if (ino) {
  55                inode = sysv_iget(dir->i_sb, ino);
  56                if (IS_ERR(inode))
  57                        return ERR_CAST(inode);
  58        }
  59        d_add(dentry, inode);
  60        return NULL;
  61}
  62
  63static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
  64{
  65        struct inode * inode;
  66        int err;
  67
  68        if (!old_valid_dev(rdev))
  69                return -EINVAL;
  70
  71        inode = sysv_new_inode(dir, mode);
  72        err = PTR_ERR(inode);
  73
  74        if (!IS_ERR(inode)) {
  75                sysv_set_inode(inode, rdev);
  76                mark_inode_dirty(inode);
  77                err = add_nondir(dentry, inode);
  78        }
  79        return err;
  80}
  81
  82static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
  83{
  84        return sysv_mknod(dir, dentry, mode, 0);
  85}
  86
  87static int sysv_symlink(struct inode * dir, struct dentry * dentry, 
  88        const char * symname)
  89{
  90        int err = -ENAMETOOLONG;
  91        int l = strlen(symname)+1;
  92        struct inode * inode;
  93
  94        if (l > dir->i_sb->s_blocksize)
  95                goto out;
  96
  97        inode = sysv_new_inode(dir, S_IFLNK|0777);
  98        err = PTR_ERR(inode);
  99        if (IS_ERR(inode))
 100                goto out;
 101        
 102        sysv_set_inode(inode, 0);
 103        err = page_symlink(inode, symname, l);
 104        if (err)
 105                goto out_fail;
 106
 107        mark_inode_dirty(inode);
 108        err = add_nondir(dentry, inode);
 109out:
 110        return err;
 111
 112out_fail:
 113        inode_dec_link_count(inode);
 114        iput(inode);
 115        goto out;
 116}
 117
 118static int sysv_link(struct dentry * old_dentry, struct inode * dir, 
 119        struct dentry * dentry)
 120{
 121        struct inode *inode = old_dentry->d_inode;
 122
 123        inode->i_ctime = CURRENT_TIME_SEC;
 124        inode_inc_link_count(inode);
 125        ihold(inode);
 126
 127        return add_nondir(dentry, inode);
 128}
 129
 130static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
 131{
 132        struct inode * inode;
 133        int err;
 134
 135        inode_inc_link_count(dir);
 136
 137        inode = sysv_new_inode(dir, S_IFDIR|mode);
 138        err = PTR_ERR(inode);
 139        if (IS_ERR(inode))
 140                goto out_dir;
 141
 142        sysv_set_inode(inode, 0);
 143
 144        inode_inc_link_count(inode);
 145
 146        err = sysv_make_empty(inode, dir);
 147        if (err)
 148                goto out_fail;
 149
 150        err = sysv_add_link(dentry, inode);
 151        if (err)
 152                goto out_fail;
 153
 154        d_instantiate(dentry, inode);
 155out:
 156        return err;
 157
 158out_fail:
 159        inode_dec_link_count(inode);
 160        inode_dec_link_count(inode);
 161        iput(inode);
 162out_dir:
 163        inode_dec_link_count(dir);
 164        goto out;
 165}
 166
 167static int sysv_unlink(struct inode * dir, struct dentry * dentry)
 168{
 169        struct inode * inode = dentry->d_inode;
 170        struct page * page;
 171        struct sysv_dir_entry * de;
 172        int err = -ENOENT;
 173
 174        de = sysv_find_entry(dentry, &page);
 175        if (!de)
 176                goto out;
 177
 178        err = sysv_delete_entry (de, page);
 179        if (err)
 180                goto out;
 181
 182        inode->i_ctime = dir->i_ctime;
 183        inode_dec_link_count(inode);
 184out:
 185        return err;
 186}
 187
 188static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
 189{
 190        struct inode *inode = dentry->d_inode;
 191        int err = -ENOTEMPTY;
 192
 193        if (sysv_empty_dir(inode)) {
 194                err = sysv_unlink(dir, dentry);
 195                if (!err) {
 196                        inode->i_size = 0;
 197                        inode_dec_link_count(inode);
 198                        inode_dec_link_count(dir);
 199                }
 200        }
 201        return err;
 202}
 203
 204/*
 205 * Anybody can rename anything with this: the permission checks are left to the
 206 * higher-level routines.
 207 */
 208static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
 209                  struct inode * new_dir, struct dentry * new_dentry)
 210{
 211        struct inode * old_inode = old_dentry->d_inode;
 212        struct inode * new_inode = new_dentry->d_inode;
 213        struct page * dir_page = NULL;
 214        struct sysv_dir_entry * dir_de = NULL;
 215        struct page * old_page;
 216        struct sysv_dir_entry * old_de;
 217        int err = -ENOENT;
 218
 219        old_de = sysv_find_entry(old_dentry, &old_page);
 220        if (!old_de)
 221                goto out;
 222
 223        if (S_ISDIR(old_inode->i_mode)) {
 224                err = -EIO;
 225                dir_de = sysv_dotdot(old_inode, &dir_page);
 226                if (!dir_de)
 227                        goto out_old;
 228        }
 229
 230        if (new_inode) {
 231                struct page * new_page;
 232                struct sysv_dir_entry * new_de;
 233
 234                err = -ENOTEMPTY;
 235                if (dir_de && !sysv_empty_dir(new_inode))
 236                        goto out_dir;
 237
 238                err = -ENOENT;
 239                new_de = sysv_find_entry(new_dentry, &new_page);
 240                if (!new_de)
 241                        goto out_dir;
 242                sysv_set_link(new_de, new_page, old_inode);
 243                new_inode->i_ctime = CURRENT_TIME_SEC;
 244                if (dir_de)
 245                        drop_nlink(new_inode);
 246                inode_dec_link_count(new_inode);
 247        } else {
 248                err = sysv_add_link(new_dentry, old_inode);
 249                if (err)
 250                        goto out_dir;
 251                if (dir_de)
 252                        inode_inc_link_count(new_dir);
 253        }
 254
 255        sysv_delete_entry(old_de, old_page);
 256        mark_inode_dirty(old_inode);
 257
 258        if (dir_de) {
 259                sysv_set_link(dir_de, dir_page, new_dir);
 260                inode_dec_link_count(old_dir);
 261        }
 262        return 0;
 263
 264out_dir:
 265        if (dir_de) {
 266                kunmap(dir_page);
 267                page_cache_release(dir_page);
 268        }
 269out_old:
 270        kunmap(old_page);
 271        page_cache_release(old_page);
 272out:
 273        return err;
 274}
 275
 276/*
 277 * directories can handle most operations...
 278 */
 279const struct inode_operations sysv_dir_inode_operations = {
 280        .create         = sysv_create,
 281        .lookup         = sysv_lookup,
 282        .link           = sysv_link,
 283        .unlink         = sysv_unlink,
 284        .symlink        = sysv_symlink,
 285        .mkdir          = sysv_mkdir,
 286        .rmdir          = sysv_rmdir,
 287        .mknod          = sysv_mknod,
 288        .rename         = sysv_rename,
 289        .getattr        = sysv_getattr,
 290};
 291
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.